An enamel paint is a paint that dries to an extremely hard, usually glossy, finish. In reality, most commercially-available enamel paints are significantly softer than either vitreous enamel or stoved synthetic resins.
Some enamel paints have been made by adding varnish to oil-based paint.
The term sometimes refers to oil-modified polyesters that were introduced in the early 1930s. The oil is required to stop or enhance the crosslinking of the paint in order to achieve sufficient flexibility of the paint film.
Typically the term "enamel paint" is used to describe oil-based covering products, usually with a significant amount of gloss in them, however recently many latex or water-based paints have adopted the term as well. The term today means "hard surfaced paint" and usually is in reference to paint brands of higher quality, floor coatings of a high gloss finish, or spray paints.